Residents who remember the big fire of 2012 at the Richmond refinery, were alarmed at Thursday night's fire when the dark sky was lit up by a giant flame coming from the very same facility.

And while Chevron is downplaying the incident, critics say the company didn't handle it well.

Chevron spokesman Kurt Glaubitz says the flaring wasn't planned, but he also wouldn't call it an emergency.

"It's important for the community to know what the community saw out there last night was really the safety systems at work. It's part of the natural safety systems we have in place at the refinery," said Glaubitz. "What was burning off was excess fuel in the unit. We were depressurizing the unit, making sure it was brought down safely."

In addition, the Richmond Community Air Monitoring Program has released a summary of the data captured during the flaring. Chevron says the report shows that the fence line monitoring equipment indicated no detection of gases outside the normal concentration ranges seen in urban environments. The Contra Costa County Department of Health said the fence line measurements of particulate matter around the refinery did elevate during the flare, but not enough to exceed state or federal limits.

Still, many in the community are not satisfied with how the events played out.

"I'm disappointed Chevron downplayed the seriousness of what happened," said Conta Costa Supervisor John Gioia, who also sits on the board of the Bay Area Air Quality Management District.

Gioia says the environmental impacts from the event are one thing, but he's almost more concerned about Chevron's response.

"This was not normal flaring. This was flaring related to a problem at a unit. Anyone looking at it could determine it was well above the level you would normally see," stated Gioia.

The deasphalting unit that experienced the problem has been shut down. Both Chevron and the Air Quality Management District will investigate the incident.

Meanwhile, skeptical residents still have doubts and fears.

"It looked like it was spewing liquid. It was coming down and cascading down the pyke and it was just burning and falling," said Matthew Carmona, a Richmond resident.

Residents say they did not receive any kind of notification from Chevron about what was going on.

The company did release a written statement to the media saying: "There has been no impact to the community and the refinery fence lines monitors are showing that the air quality is well within quality standards."

"They have that there to control the massive PR situation," said Shy Simmons, also a resident, of Chevron's media statement.

Mayor-elect Tom Butt says that's a problem that needs addressing.

"I don't think we have a health issue here. We do have an issue of informing the public of what's going on," he said.

Butt says he didn't hear from Chevron until two hours after the flare started burning. His public health experts assured him that air quality had not been impacted, but he says people need to know what's happening right away.

"It's just not right to scare people like that and let them hang-around a couple hours and wonder what's going on. We've got to find some way to get ahead of that," said Butt.

Contra Costa County Supervisor John Gioia tweeted out that flare gases at Chevron include hydrocarbons, carbon dioxide, particulate matter and other compounds and that Hazmat inspectors were on scene and monitoring.

Flames and water vapor became visible when a process unit at the refinery needed to be depressurized and shut down, according to Chevron spokesman Braden Reddall.

"The process produces a flare, and water vapor that looks like smoke, and makes it possible to shut down the unit safely," Reddall said.

Reddall said fence line air quality monitors showed no impact to the community. He added that he could not discuss why the unit needed to be depressurized due to the "commercial sensitivity" of refinery operations.

The director for the Global Community Monitor said data from those same monitors shows high levels of fine particulate matter, which is unhealthy for people.

"The majority of the wind direction is blowing out over the bay, so it's not impacting the community of North Richmond," Marioka said.

ABC7 News reporter Amy Hollyfield and Bay City News contributed to this report